1. Field of the Invention
The present invention relates to a magnetic head for a magnetic disc and a method for manufacturing the same and, in particular, to a magnetic head for a magnetic disc, in which a plurality of head cores having different recording densities are disposed adjacent to one another, and a method for manufacturing the same.
2. Related Art
As a conventional magnetic head for a magnetic disc, for example, there is known a magnetic head having such a structure as shown in FIGS. 9 and 10. The present conventional magnetic head includes a head core 1a, which is mounted on a head arm (not shown) of a magnetic disc device and can be slidingly contacted with the recording surface of a magnetic disc for magnetic recording and reproduction, and a head core 1A for erasing the magnetic records of a magnetic disc in order to restrict the width of a track.
In the head cores 1a and 1A, there are formed gaps G1 and G2 respectively. In such a manner that the head cores 1a and 1A are held by and between a wear resistant slider 2A and a wear resistant slider with a groove 3A both of which can be slidingly contacted with the recording surface of the magnetic disc, these head cores 1a and 1A are retained by a ferrite ring 4A which shields against the external magnetism.
That is, an erasing coil 5A for erasing the magnetic records of the magnetic disc is fitted into the interior portion of the erasing head core 1A, while a recording and reproducing coil 6A for recording and reproducing the recording information of the magnetic disc is fitted into the interior portion of the recording and reproducing head core 1a. Also, a back core 7A for forming a magnetic path is disposed in contact with the lower portions of the head cores 1a and 1A.
Now, in a personal computer or the like which incorporates a magnetic disc device therein, there is required a magnetic disc device which not only is capable of mounting therein a magnetic disc having a storage capacity of 1 MB or 2 MB recordable and reproducible by a magnetic head including the above-mentioned head cores 1a and 1A but also is capable of mounting therein a magnetic disc having a storage capacity of 100 MB in compliance with a request for an increase in the storage capacity. For such high-density recording magnetic disc device, it is also desired that a conventionally used magnetic disc having a storage capacity of 1 MB or 2 MB can also be used therein.
However, under the present conditions, the above-mentioned high-density recording magnetic head is manufactured as an entirely different structure from the magnetic head having a storage capacity of 1 MB or 2 MB. That is, the magnetic disc having a storage capacity of 1 MB or 2 MB and the magnetic disc having a storage capacity of 100 MB, which are not different in outer appearance, cannot be magnetically recorded or reproduced by the same magnetic head.
In view of the above, there has been proceeding the development of a magnetic head which is structured such that it has not only a normal recording head core for a storage capacity of 1 MB or 2 MB but also a high-density recording head core for a storage capacity of 100 MB. However, when the normal recording head core for a storage capacity of 1 MB or 2 MB and the high-density recording head core for a storage capacity of 100 MB are simply united together, not only the above-mentioned head cores 1a and 1A are held by and between the sliders 2A and 3A and the back core 7A is fixed to the head cores 1a and 1A, but also the high-density recording head core is mounted on the slider 2A or 3A.
In this case, although the normal head core and high-density head core can be united together, the number of parts of such structure is large, which accordingly increases the time and labor of a process for assembling the parts of the magnetic head, so that the productivity of such magnetic head cannot be enhanced.
The present invention aims at eliminating the drawbacks found in the above-mentioned conventional magnetic head.
It is an object of the invention to provide a magnetic head for a magnetic disc and a method for manufacturing the same which can enhance the productivity thereof by incorporating therein a plurality of head cores having different recording densities in an integral manner.
It is another object of the invention to provide a magnetic head for a low order floppy disc as well as a high-density floppy disc, in which coils can be wound easily.
According to the present invention, there is provided a magnetic head for a magnetic disc, characterized in that: there are formed a plurality of cut-out portions in an integrally formed slider, a plurality of head cores having different recording densities are respectively inserted into the plurality of cut-out portions, and the plurality of head cores having different recording densities are mounted in the integrally formed slider, that is, in the same slider.
Also, according to the present invention, there is provided a method for manufacturing a magnetic head for a magnetic disc, which comprises the steps of: cutting a slider block to form a plurality of cut-out portions to thereby produce an integrally formed slider; inserting and fixing a plurality of head cores having different recording densities into the plurality of cut-out portions respectively; and mounting the plurality of head cores having different recording densities into the integrally formed slider or in the same slider.
Further, according to the present invention, there is provided out of the above-mentioned plurality of cut-out portions, a first cut-out portion allowing a first head core to be inserted thereinto and a second cut-out portion allowing a second head core to be inserted thereinto are opened up in the same surface of the slider and are arranged in parallel to each other, and the plurality of head cores are mounted in the slider in such a manner that they are arranged in parallel to each other.
Still further, according to the present invention, there is provided the first cut-out portion, into which the first head core can be inserted, is formed in such a manner that it is opened up in one surface of the slider; the second cut-out portion, into which the second head core can be inserted, is opened up in the other surface of the slider on the opposite side thereof to the one surface, and the second cut-out portion is formed in such a manner that it extends on the same line as the first cut-out portion; and, the plurality of head cores are mounted in the slider in such a manner that they respectively extend on the same line.
Yet further, according to the present invention, there is provided the first cut-out portion for insertion of the first head core is formed in such a manner that it is opened up in one surface of the slider; the second cut-out portion for insertion of the second head core is opened up in the other surface of the slider on the opposite side thereof to the one surface; and, the plurality of head cores are mounted in said slider in such a manner that they alternate each other in position.
In attaining the above object, according to the invention, there is provided a magnetic head for a floppy disc, comprising: a slider; a plurality of cut-out portions respectively formed in the slider such that they extend vertically from one side surface of the slider and extend through the slider in the vertical direction thereof; a plurality of head cores having different recording densities and formed to be inserted into their respective ones of the above-mentioned cut-out portions; a plurality of coil winding grooves formed in the slider such that they extend vertically from the slider one side surface and define head core hold portions in the top and bottom portions of the slider; and, recording and reproducing coils respectively wound around their respective head cores within the coil winding grooves, wherein the coil winding grooves include, in the slider one side surface, one or more partition walls existing between the plurality of cut-out portions.
Also, in achieving the above object, according to the invention, there is provided a magnetic head for a floppy disc, in which each of the partition walls is an intersecting point portion between the plurality of coil winding grooves formed in the above-mentioned slider one side surface such that they extend obliquely at a given angle of inclination in two directions from the area of the slider existing between the plurality of cut-out portions.
In a magnetic head according to the invention, preferably, the above-mentioned inclination angle of the coil winding grooves may be set in the range of 30 degrees to 60 degrees.
The above-mentioned means or measures operate respectively in the following manner:
That is, according to the present invention, since a plurality of head cores having different recording densities can be mounted in the same slider, even if magnetic discs having different recording densities are mounted, the present magnetic head is able to perform magnetic recording and reproducing operations in correspondence to the respective recording densities. At the same time, because the slider is formed as an integral member, the number of parts of the present magnetic head can be reduced as well as the productivity of the present magnetic head can be enhanced.
Also, according to the present invention, there is provided a method for manufacturing a magnetic head for a magnetic disc in which a slider block is cut to form a plurality of cut-out portions to thereby produce an integrally formed slider, a plurality of head cores having different recording densities are inserted into and fixed to the plurality of cut-out portions respectively, and the plurality of head cores having different recording densities are mounted into the integrally formed slider or into the same slider. Due to this, the slider can be produced as an integral member, so that the number of parts of the present magnetic head can be reduced, the productivity thereof can be enhanced, and the manufacturing cost thereof can be cut down to a lower level.
Further, according to the present invention, since the plurality of head cores can be mounted in such a manner that they are arranged in parallel to each other, the respective cut-out portions can be formed from the same direction, which not only facilitates the forming process of the cut-out portions but also can increase the strength of the other surface side of the slider.
Still further, according to the present invention, because the plurality of head cores can be mounted in the slider in such a manner that they respectively extend on the same line, the head pressures of the respective head cores to be in sliding contact with the recording surface of the magnetic disc can be set at the same level.
Yet further, according to the present invention, due to the fact that the plurality of head cores can be mounted in the slider in such a manner that they alternate each other in position, the plurality of head cores can be mounted in parallel to each other at mutually spaced positions, thereby being able to prevent interference between the plurality of head cores.
According to the above-mentioned structure, since a head core for a low order floppy disc and a high density head core for a high-density floppy disc are assembled into the same slider, both of the above-mentioned floppy discs can be recorded and reproduced by the present magnetic head. Also, because the coil winding grooves each includes a partition wall between the plurality of cut-out portions of the present invention, or because the coil winding grooves extend obliquely in two directions from the area of the slider one side surface existing between the plurality of cut-out portions according to the present invention, there can be defined mutually independent coil winding grooves or coil winding grooves which are independent of each other and each of which has a triangular-shaped section.
Due to this, when winding the coils around the core half sections of the corresponding head cores respectively, there is eliminated the possibility that the coil can be entangled around the core half sections of the other head cores or with the coils to be wound around the core half sections of the other head cores, thereby being able to improve the coil winding efficiency of the magnetic head.
Also, according to the present invention, especially since the coil winding grooves do not extend in parallel to one side surface of the slider but extend in such a manner as to form a triangular shape, the amount of cutting of the slider when the coil winding grooves are formed by cutting the slider can be reduced, so that the time necessary for cutting or machining of the coil winding grooves can be shortened.
Further, in connection with the head core hold portions that are defined by the thus formed coil winding grooves of the slider, the rigidity of the slider in the thickness direction thereof is increased, thereby being able to improve the flatness of the disc sliding surface of the slider.
When the inclination angle of the coil winding grooves is set in the range of 30 degrees to 60 degrees, the spaces of the coil winding grooves, which respectively have a triangular-shaped section and are used to wind the coils, can be used effectively to thereby be able to reduce the amount of cutting of the coil winding grooves. This also makes it possible to increase the rigidity of the slider as greatly as possible.